1. Technical Field
The present invention relates to an electro-optical device used for a personal computer or a cellular phone and to an electronic apparatus using the same.
2. Related Art
In recent years, electro-optical devices, such as liquid crystal display devices, have come into widespread use as display devices of electronic apparatuses, such as a personal computer and a cellular phone. For example, in general, a transmissive or reflective liquid crystal display device has a structure in which a flexible substrate is connected to a liquid crystal panel, a light source, such as an LED (light emitting diode), is mounted on a portion of the flexible substrate opposite to the liquid crystal panel, and the flexible substrate is bent to arrange the light source on a light receiving surface of an optical waveguide.
However, in this case, there is a fear that the light source, such as an LED, will be detached from the light receiving surface of the optical waveguide by bending stress of the flexible substrate. In addition, in order to connect a connector of the flexible substrate to an external device on a surface of a liquid crystal panel opposite to a display surface, or to accommodate the flexible substrate, the flexible substrate should be bent to be adhered to the liquid crystal display panel or to members arranged on the rear surface of the liquid crystal panel. In this case, the flexible substrate may be detached therefrom by bending stress thereof.
Therefore, in order to prevent the positional deviation of the light source, such as an LED, or the detachment of the flexible substrate, a flexible substrate that has a fourth region for connecting a second region where a light source of the flexible substrate is arranged and a third region opposite to the second region has been suggested (for example, see JP-A-2004-133108 (paragraph [0048] and FIG. 4)).
However, according to the above-mentioned flexible substrate, when the flexible substrate is bent to be arranged on a surface of a liquid crystal panel opposite to a display surface, the thickness of a liquid crystal display device increases by a thickness corresponding to the bent portion of the flexible substrate. In addition, the flexible substrate should be bent in order to arrange the light source on the light receiving surface of the optical waveguide, which causes the length of the flexible substrate to be larger. Thus, this structure has a problem in that a reduction in the size and thickness of an electro-optical device is not achieved. Further, since the bent region is narrow, it is difficult to secure a sufficient area to mount wiring lines and electronic components. In addition, in order to secure a sufficient area, it is necessary to increase the size of the flexible substrate.
Furthermore, this structure causes weak bonding stress of the flexible substrate, but strong stress may occur according to the width of the bent portion.